Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Mitigation of Hum in Radio Transmission

Status
Not open for further replies.
M

muhammad11

Member level 2
Joined
Nov 1, 2013
Messages
43
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
1,572
I have listen many radio stations live programs on my radio receiver & noticed that a great amount of hum in voice. Also i noticed that hum is inbuilt in their transmission so there is no question of fault in receiver. My QUESTION IS THAT IS THERE ANY SMART TECHNIQUE OR SIMULATION TECHNIQUE TO REMOVE HUM FROM VOICE (AUDIO SIGNAL) DURING LIVE TRANSMISSION OR IS THERE ANY WAY TO REMOVE HUM FROM OLD TRANSMITTERS???
Radio or TV technicians or engineers should answer please.
 

I have never noticed hum in transmissions before, are you certain it is part of the transmission and not being introduced in your receiver?

Tell us more:
1. is the hum low frequency (50/60/100/120 Hz for example?)
2. are you haering the hum on AM or FM stations or both?

A high pass filter will block the hum but if it is modulating the audio itself there might be mixing effects that directly modulate the signal in the voice frequency range.

Brian.
 

Having worked in broadcast for 40 years, I can say that UK Broadcasts are virtually hum free, or at least -80dB with respect to peak modulation. Some times on "live" transmissions hum is present but that is due to faults at the source.
FWIW All high power transmitters use three phase bridge rectification, so the ripple frequency would be 300 HZ, some even use delta bridge plus star bridge which doubles the ripple to 600 HZ.
Frank
 

If you filter away the hum on your radio then you also filter away the deep low frequencies from a man's voice then he will sound like idiot soprano guys from "over there" (a TV documenary showed thousands of them in a call center in Pakistan) who phone me every day trying to sell "duck cleaning". You will also filter away deep low frequency bass sounds from music.
 

Audioguru said:
If you filter away the hum on your radio then you also filter away the deep low frequencies from a man's voice then he will sound like idiot soprano guys from "over there" (a TV documenary showed thousands of them in a call center in Pakistan) who phone me every day trying to sell "duck cleaning". You will also filter away deep low frequency bass sounds from music.
Click to expand...

Actually I have noticed in pk n india radio transmission there is a lot of hum(50 Hz) in transmission.How this hum and noise will be removed.Please explain how to remove this hum?
 

If the hum has constant level and frequency, it can be effectively removed with digital signal processing means. Simple notch filters would give nasty artifacts.
Actually I have noticed in pk n india radio transmission there is a lot of hum(50 Hz) in transmission.
Click to expand...
Is it an AM station? 50 Hz sounds somewhat unlikely. Insufficiently filtered transmitter supply would give 100, 150, 300 or 600 Hz, as explained above. 50 Hz crosstalk into the audio path won't be actually expected for professional equipment.
 

muhammad11 said:
Actually I have noticed in pk n india radio transmission there is a lot of hum(50 Hz) in transmission.How this hum and noise will be removed.Please explain how to remove this hum?
Click to expand...
I betcha it is your radio that produces the hum, not more than one transmitter.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top